Refuse packing system and method

ABSTRACT

A refuse packing and storage system in which successive batches of refuse are packed against a longitudinally movable panel within the refuse storage compartment, and wherein movement of the panel in a direction to increase the size of the storage compartment is permitted in response to packing forces.

United States Patent Inventor John McCarthy Dearborn, Mich.

Appl. No. 748,857

Filed July 30, 1968 a Division of Ser. No. 516,603, Dec. 27, 1965,

Patent No. 3,410,427.

Patented Jan. 19,1971

Assignee Gar Wood Industries, Inc. a corporation of Michigan REFUSEPACKING SYSTEM AND METHOD 5 Claims, 7 Drawing Figs.

US. Cl 214/152 Int. Cl B651 3/00 Field of Search 214/833,

[56] References Cited UNITED STATES PATENTS 3,049,256 8/1962 Urban214/518 3,220,586 11/1965 Gollnick 214/833 3,257,012 6/1966 Berolzheimer214/83.3X

Primary Examiner-Albert J. Makay Attorney--Harness, Dickey & PierceABSTRACT: A refuse packing and storage system in which successivebatches of refuse are packed against a longitudinally movable panelwithin the refuse storage compartment, and wherein movement of the panelin a direction to increase the size of the storage compartment ispermitted in response to packing forces.

PATENTEDJANISIHTI 3.556324 SHEET 1 0F 2 INVENTOR.

. 1 REFUSE PACKING SYSTEM AND METHOD This application is a divisional ofapplication Ser. No. 5l6,603 filed Dec. 27, i965, now U .S.. Pat. No.3,4l0.427, and is directed to the method disclosed in thatpriorapplication. i

The present invention relates generally to refuse packing and storagesystems, and more particularly to those including a refuse storagecompartment havingmeans located at one end thereof for loading the looserefuse and for then compact- For the first several charges compacted bythe compaction panel against the ejector panel, full designed compactionwill be obtained and the ejector panel will be released to moveforwardly and increase the area of the storage compartment to the rearthereof because the force received on its rear face caused by thecompaction panel and transmitted through the relatively small amount ofrefuse will be greater than 0.9x

ing it as it transfersit .into the refuse storage compartment, as

well as the method of controllingfsuch compacting. The present systemmay be used in connection with either stationary or mobile equipment,but for purposes of present'description'will be described associatedwith a refuse carrying vehicle having loading and compacting means atits rearward end in the tail gate thereof.

Refuse vehicles having rear end or tail gate loading and compactingmechanisms are well known in the art, and the ob ject of using' suchcompacting mechanisms is'to increase the density of therefuse carried bythe vehicle so thata maximum quantity of input refuse material maybehandled by the vehiplace and unloaded, often a ratherlengthyandtime-consuming trip. In stationary equipment the object is to increasestorage capacity for a given size unit and thereby lengthen the durationbetween unloading operations.

Known compacting mechanism have for the most part in-' cluded one ormore power operated swinging, sliding or reciprocating panels which pushthe refuse under force into the storage compartment of the unit. Thepresentinvention is shown embodied in a system having such a mechanism,specifically one including a pair of-swinging panels, butis not solimited. Such a system is shownin U.S.'lat.No. 2,879,906.

Certain of the more recent refuse-vehicles on the market have increasedtheir compaction efficiency by providing a longitudinally moving panelin the storage compartment against which refuse is packedo'r'compacted'from thefirst' load until thestorage compartmentisfilled,-and which also is used to eject the load in the vehicle whenit is filled and ready for unloading. Such ejector panels, astheyare-often referred to, are positioned at the rear end of the storagecompartment adjacent the coinpacting mechanism at the beginning of thepacking cycle when the truck is empty. Refuse is loaded and compactedagainst this plate until some degree of fullness or density is reached,whereupon the ejector panel is moved forwardly a relatively smalldistance, either manually or automatically, to provide room for theloading and compaction of additional refuse. Consequently, each chargeof material passing through the compacting mechanism is compacted eitheragainst the ejector panel or against earlier charges of thematerial'which have been previously compacted against such panel.Systems of this type, if properly controlled, can give greatercompaction density than those which do not pack against such an ejectorpanel, and it is this ejector panel type system to which the presentinvention is directed.

As can be appreciated, the manner in which the forward movement of theejector panel is controlled is a primary factor in the performance ofthe unit in'terrns of degree of compaction. One method by which this hasbeen done is to providemeans for releasing the ejector panel, whereby itmay then be forced forwardly by the expanding refuse and/or pushingforce of the compaction mechanism, when a predetermined force is exertedon the rear face of the ejector panel. Such systems, whether they bemechanical or hydraulic, have several disadvantages. One suchdisadvantage arises from the fact that there is a substantial amount offriction between the refuse and the sides of the storage chamber'as therefuse is pushed forwardly therein by the compacting mechanism. Theresulting difficulty may be best understood from the following example:Assume that the compacting panel is adapted to exert a compacting forceof X pounds across the cross-sectional area of the storage compartmentand that the ejector panel is adapted to be released upon theapplication against its rear cle before it must be driven to adurnp orother appropriate v pounds.'However, as the storage compartment becomesincreasingly full the exertion of X pounds of force against the refuseby the compaction panel in a given cycle results in the exertion uponthe rear face of the ejector panel of a force which is-substantiallyless than i X or even 0.9X pounds because a progressively increasingproportion of the force exertedby the compaction panel is absorbed orreacted against by frictional forces along the bottom, sides and top ofthe storage compartment, Consequently, as the storage compartmentbecomes fuller the amount of movement forwardly of the ejectorpanelbecomes less per compaction cycle, until eventually the compactingpanel is unable to cause any further forward movement of the ejectorpanel and no additional refuse may be loaded without stallingthecompaction panel. In systems of this type, whether they be hydraulicor mechanical, this .point is often reached before the ejector panel ismoved all the way to thefront end of the storage compartment, andconsequently storage capacity is lost and the total amount of refusewhich may be handled by the unit in one filling is reduced. This problemcannot really be avoided by setting the system so that it takes a muchsmaller force upon the rearface of the ejector panel to cause it to bereleased, because if this is done the degree of compaction from the veryfirst load on is reduced proportionately andthe overall capacity of theunit is then reduced not because the entire storage chamber is not usedbut because there is a'lesser degree of compaction of the refusematerial.

ln'such systems which are hydraulic and utilize telescopic cylinders forcontrol of the ejector panel this problem is compounded because ofthedifferential areas of the respective cylinders. For example. considera system which is designed so that the ejector panel cylinder ispermitted to dump to tank.

when the pressure therein created by forces .on the rearward face on thepanel reaches a predetermined value. When the first loads are compactedin the unit the ejector panel is at the rear of the storage compartmentand the telescopic cylinders fully extended, and the force on the rearface of the ejector panel necessary to cause this predetermined pressurein the ejector cylinder for release will be this predetermined pressuremultiplied by the cross-sectional area of the rearmost and smallestcylinder of the telescopic cylinder assembly. As the storage compartmentfills the larger cross-sectional area cylinders of the telescopiccylinder assembly come into use, and again the force necessary to causethe ejector panel to release will be the predetermined pressure in theejector cylinders multiplied by the cross-sectional area of that stagethereof being actuated at that time. However, since this stage isnecessarily larger in cross-sectional area than-the previous one, theforce necessary to cause the panel to release is also larger.Consequently, the fuller the storage compartment the greater must be theforce applied to the rear face of the ejector panel to cause it torelease. In designing such a system it is therefore not possible toprovide for the application of maximum compaction forces for the earlystages of compaction, since as the compartment becomes filled therewould be insufficient force available to even move the later largerdiameter stages of the telescopic ejector cylinder. As a result, smallerinitial compaction forces must be settled for, with the attendant lossof com paction efficiency. It can thus be seen that the aforementioneddisadvantages of a system responsive to forces on the rear face of theejector panel, are greatly amplified when a telescopic cylinder is usedfor the ejector cylinder.

The problems created by the aforementioned disadvantages aresubstantially further amplified as the size of the storage compartmentis increased in volume and length. This is because larger and longerstorage chambers require telescopic cylinder assemblies having a greaternumber of stages, and because the increased inside surface area of suchchambers increases the friction forces resisting movement of the refuseforwardly in the chamber. Since the current trend is towards larger andlonger storage units, these problems present design restrictions whichare of increasing significance.

Systems which are manual in nature, wherein forward movement of theejector panel is caused by the manipulation of manual controls, sufferthe disadvantage that the efficiency of the system depends upon theability of the operator to accurately gauge when the ejector panelshould be moved forwardly, as well as the amount of movement when somoved, and generally speaking operators of equipment of this nature arerelatively unskilled. Systems which provide for a releasing of theejector panel at the completion of each compaction cycle, or at someother time period, suffer the disadvantage that during the period oftime from the completion of one compaction cycle to the initiation ofthe next compaction cycle the natural expansion of the previouslycompressed refuse may cause the ejector panel to move forwardly agreater distance than is desired for an optimum degree of compaction.and consequently overall compaction efficiency is reduced.

It is therefore a primary object of the present invention to provide asystem of the general type discussed above which is relatively simple inconstruction and method of operation, and which avoids theaforementioned disadvantages of other known systems, whereby maximumloading of a given storage compartment, both in terms of extent offilling and degree of compaction. may be obtained. It is a relatedobject to provide such a system utilizing a hydraulically driven packingpanel and an ejector panel actuated by a hydraulic telescopic cylinderassembly.

These and other objects of the present invention will become apparentfrom consideration of the specification taken in conjunction with theaccompanying drawings in which there are illustrated two embodiments ofthe present invention, and wherein:

FIG. 1 is a side elevational view, partially broken away, showing themajor portion of a refuse vehicle in which the present invention may beembodied;

FIGS. 2, 3, and 4 are similar to FIG. I but with substantial partsbroken away to shown an operating cycle of the loading and compactingsystem of the vehicle;

FIG. 5 is a diagrammatic view showing a hydraulic control circuit forthe system of FIGS. 1-4, embodying the principles of the presentinvention;

FIG. 6 is an enlarged sectional view of one of the valves forming a partof the circuit shown in FIG. 5', and

FIG. 7 is a diagrammatic view of a portion of the circuit shown in FIG.5, illustrating a modification thereof.

The present invention may be embodied in many different types of refusecompacting systems, including both stationary and mobile systems, andthose having single as well as double panels in the loading andcompacting mechanism; however, for purposes of present illustration itis shown herein embodied in a refuse vehicle of the general type in US.Pat. No. 2,879,906. As can be seen, the unit comprises a conventionaltruck chassis 10 to which is secured a storage compartment 12 having atthe rearward open end thereof a tail gate assembly 14 pivotally securedto the storage compartment, as by hinges 16, to enable it to be swungupwardly by a tail gate piston and cylinder assembly 18, secured at oneend to the storage compartmeut and at the other end to the tail gate,when it is desired to unload the refuse compartment. Tail gate assembly14 includes a lower cylindrical portion defining a trough into whichrefuse may be loaded, a rotating sweep panel 22 for sweeping the refuseout of trough 20 and bringing it to an elevation substantially in linewith the bottom of the storage compartment, and a pivotally mounted rampanel 24 for moving the loaded refuse from the top of the sweep paneland compacting it into storage compartment 12. Sweep panel 22 may bepowered by a rotary hydraulic motor 26 through a conventional sprocketand chain drive mechanism 28, and ram panel 24 may be powered by ahydraulic double acting piston and cylinder assembly 30 secured at oneend to the tail gate assembly and at the opposite end to ram panel 24.Both sweep panel 22 and ram panel 24 extend substantially the full widthof the storage compartment and tail gate assembly, and the latterextends substantially the 'full width of the storage compartment. 1

Inside the storage compartment there is provided an ejector panel 32which has a cross-sectional area substantially the same as that of thestorage compartment'and which is adapted to move forwardly andrearwardly longitudinally of the vehicle. Ejector panel 32 may bepowered bya conventional double acting telescopic piston and cylinderassembly 34 secured at one end to the base of the ejector panel and atits opposite end to the forward wall of the storage compartment.

In FIG. 5 there is illustrated a representative hydraulic circuit for arefuse system such as shown in the preceding FIGS. It includes a tank orreservoir 36 for the hydraulic fluid, and a pump 38 the inlet of whichis connected to tank 36 by a fluid supply line 40. The pump may bedriven in the usual fashion by the vehicle engine. In a stationarysystem it could be electrically driven. The outlet of pump 38 isconnected to a main control valve 42 by mcans of a fluid supply line 44.Control valve 42 is connected to rain cylinder 30 by means of a fluidsupply line '46 (for packingstroke) and a fluid return line 48. to tailgate cylinder 18 by means ofa fluid supply line 50 and a fluid returnline 52, to hydraulic sweep motor 26 by means of a fluid supply line 54and a fluid supply line 56, and to telescopic ejector cylinder assembly34 by means of a fluid supply line 58 (for ejection stroke) and a fluidreturn line 60. Control valve 42 is connected directly to tank 36 bymeans of a fluid return line 62. Control valve 42 which in the usualsystem comprises a plurality of valves, is provided with the usualactuating handles 64 for powering the ram cylinder, tail gate cylinder,sweep motor and telescopic ejector cylinder assembly, respectively, inthe conventional manner. All of the circuit described up to this pointis believed to be typical of known circuits and may be varied numerousways by those skilled in the art to achieve the particular functiondesired since it is not per se a part of the present invention but onlyone representative circuit to which this invention is applicable.

The primary distinguishing feature of the subject circuit is theprovision of a pilot operated dumping valve 65. This valve, which willbe described in greater detail below, is connected by means of fluidline 66 to ejector cylinder supply line 58, by means of fluid line 68 toram cylinder supply line 46, and by means of fluid line 70 to tank 36.This valve operates to permit the dumping to tank of fluid from theejection stroke side of the ejector cylinder in response to and upon thereaching of a predetermined pressure in the power or packing stroke sideof the ram cylinder.

As can be seen in FIG. 6, pilot operated dumping valve 65 comprises abody 72 having a valve bore 74 therein. Fluid line 66 communicates withvalve bore 74 by means of a passageway 76, and fluid line 70 by meansofa passageway 78. Disposed within the bore 74 is a valve spool adaptedto slide longitudinally therein from a first position in whichcommunication between lines 66 and 70 is blocked (the position shown inFIG. 6) and a second position wherein line 66 is placed in communicationwith line 70 by means of a groove 81 in spool 80. Secured to one end ofhousing 72 is a cover structure 82 having a bore 84 therein in alignmentwith bore 74. Movement of valve spool 80 is caused on the one hand bymeans of a compression return spring 86 disposed within bore 84 andpushing against one end of spool 80, and on the other hand by means of asmall piston 88 actuated by the pressure in fluid line 68 and engagingthe opposite end of spool 80. Thus, as can be seen, the valve spool isnormally maintained in the position shown in FIG. 6 whereincommunication between lines 66 and 70 is blocked. However, upon theapplication of a predetermined amount of pressure to line 68, the forceexerted on the spool in the downward directionQas shown in FIG. 6,.bysmall piston 88 will overcome the counteracting force exertedjby' returnspring 86 and the valve spool will move downwardly to place fluid line66 in communication with fluid line 70. Return spring 86 is preferably alow rate spring so that the valve will not operate as a metering valvein which the flow into fluidline 70 is to some extent proportional tothe pressure in line 68. On the contrary, if it is desired that thevalve operate as an on-off valve which ideally is fully off when thepressure in fluid line 68 is below a predetermined valve and which isfully on when such pressure is at or above this predetermined valve. Theactual pressure at which the spool will shift may be varied somewhat bymeans of an'adjusting screw 90 which engages a stop member 92 supportingthe lower end of return spring 86. Passageways 94 and 96 are provided inthe spool and housing respectively to provide an escape for the normallyencountered leakage.

The method of operation of the system is asfollows: In FIG. 2 thestorage compartment is shown partially filled and the system in an atrest condition in which ram panel '24 is in its forwardmost positionholding the refuse, indicated at 98, tightly against ejector panel 32,and in which the sweep panel has been rotated to a position clear ofhopper so that the latter is ready to receive the next load of refuse.When the hopper has been filled the proper actuatingcontrol is operatedand sweep panel 22 starts to rotate in a counterclockwise direction. Asit clears ram panel 24 the latter starts moving rearwardly, and thesweep panel continues its counterclockwise rotational movement, engagingthe refuse and sweeping it up towards the storage compartment: In FIG. 3the system is shown justafter the sweep panel has engaged the refuse andis starting to. push it forwardly and upwardly. This movement ofthe'sweeppanel continues until the refuse is raised to a levelsubstantially in line with the bottom of the storage compartment. atwhich time full-power is applied to the ram panel and it sweeps therefuse off the upper surface of sweep panel 22 and pushes it withmaximum force into the storage compartment against ejector panel 32.FIG. 4 shows the system midway in this step of the cycle.

As will be appreciated, during'c'ompaction the pressure on the powerside of ram cylinder 30, i.e., in fluid line 46, will be substantially.proportional to the compactingforces on the refuse in the storagecompartment exerted by the'ram'panel. When this force, and hence ramcylinderpressure, reaches a predetermined value, the pressure in fluidline will cause pilot operated valve 65 to pop open and dump fluid fromthe power stroke side of ejector cylinder, whereupon the latter will bepushed forwardlyby the continued forward movement of ram panel 24.However, since the dumping of the ejector cylinder reduces the reactiveforces acting against the ram panel, the pressure in the ram cylinderdecreases and when it drops below the predetermined value valve 65closes and further forward movement of the ejectorpanel is arrested.Control valve 42. will have no influence on this operation because theejector cylinder is not being actuated. during the It has'beendiscovered that very good results are obtained when valve 65 isdesignedand adjusted so that it will open when the'pressure in the ram cylindersupply line'is approximately 80percent' of the maximum'pressure reachedin that line, as determined by the usual relief valve. This figure of 80percentprovides a consistently high degree of compaction and yet issufficiently below the pressure setting of the relief valve (100percent) that no fluid is likely todump across the relief valve. withthe attendant losses in power and efficiency. as well as heating of thehydraulic fluid..ln other words. it has been found that a 20 percentsafety factor will give excellent compaction without getting too closeto the dumping pressure of the ram cylinder relief valve, which as1willbe appreciated will vary somewhat in an actual production valve due tomanu facturing'tolerances and hysteresis. It also accounts for any exertincreasingly greater reactive forces asthe compartment becomes morefilled. I

In the circuit shown in FIG. 5, fluid line 68 is shown connected to thesupply line for the ram cylinder. This arrangement is preferable insystems where there is a possibility that one of the other hydraulicfunctions performed by the overall system will require the use ofpressures in excess of the predetermined pressure setting of dumpingvalve 65 which might cause the dumping valve to dump fluid from theejector cylinderduring some other cycle of the system, such as when Ithe ejector cylinder is being used to eject the load from the compactioncycle, and therefore fluid lines 58 and 60 will be 1 closed in thecontrol valve, in the usual manner. In addition, any safety relief valveprovided in the ejector cylinder circuit will be set at a pressurehigher than any encountered during the compacting cycle, so that it alsowill not influence this operation.

It has been found that in actual operation of the present system theejector panel tends to index forwardly insmall rapid increments. Sinceits movement is arrested whenever the ram cylinder pressure is below thepredetermined value the refuse is substantially continually subjected toat least the compacting force created by the ram "panel under theinfluence of this predetermined pressure. This provides an advantageover systems which permit a complete releasing of the ejector panelafter the ram panel has completed its packing stroke since in suchsystems the refuse is allowed to expand to g a lower degree ofcompaction, pushing the ejector panel further forwardly than desirable.

storage compartment, or when the tail gate is raised, or the like.

In systems where this is not likely to occur, it has been found that theline for control fluid to dumping valve 65 may be connected directly tothe main supply. line from the pump. Such an arrangement is shown inFIG. 7,.wherein dumping valve- 65 is shown connected to fluid supplyline 44 by means of fluid line 680. As can be seen, this FIG. isidentical in all respects to FIG. 5, except'that the dumping valve isconnected to supply line 44 rather than supply line 46, and thereforethe same reference numbers are used. Since in many systems the maximum'pressure encountered, for all the hydraulic functions contemplated, isthe pressure used to actuate the ram panel to compact the refuse intothe storage compartment, a circuit of the type shown in FIG. 7 is oftenperfectly satisfactory.

When the storage compartment is full unloading is accomplished byraising the tail gate, using piston and cylinder assembly l8, andactuating ejector panel 32, which is in its forwardmost position whenthe compartment is filled, to cause it to move rearwardly to eject orpush the refuse out of the compartment. In circuits of the type shown inFIG. 7 there is virtually no risk that the dumping valve will be openedby the supply of fluid under pressure to the ejector cylinder forejecting the load, since it has been found that pressures required forthis purpose are substantially below the pressures encountered in theram cylinder during packing, as well as substantially below thepredetermined pressure setting.

Thus there are disclosed in the above description and in the drawingsseveral exemplary systems embodying the method of the present inventionwhich fully andefiectively accomplish the objects thereof. However, itwill be apparent that variations in the details thereof may be indulgedin without departing from the sphere of the invention herein described,or the scope of the appended claims.

Iclaim:

I. A method of compacting batches of refuse into a refuse storagecompartment having an opening at one end, a first panel mounted thereinfor movement away from said one end and a packing panel for packingrefuse into said compartment through said opening. comprising: holdingthe first panel against movement away from said one end; moving thepacking panel to pack a batch of refuse into the compartment at said oneend thereof against the first panel; sensing the packing force exertedby the packing panel on said batch of refuse; and releasing the firstpanel for movement away from said one end when said packing forcereaches a predetermined value sufficient to provide the desiredcompaction. said predetermined value remaining substantially constantfor all degrees of compartment filling.

2. The method as claimed in claim 1, wherein the first panel is releasedfor movement away from said one end in progressive steps. one step eachtime said packing force reaches said predetermined valve.

3. The method as defined in claim lefurther including the step ofreestablishing said holding step following the performance of saidreleasing step.

4. The method as defined in claim 1. further including repeating saidholding. moving, sensing and releasing steps in a plurality ofcycles ofsaid steps.

5. The method as claimed in claim 1. comprising the further step ofmoving the first panel toward said oneend to force packed refuse out ofthe storage compartment.

1. A method of compacting batches of refuse into a refuse storagecompartment having an opening at one end, a first panel mounted thereinfor movement away from said one end and a packing panel for packingrefuse into said compartment through said opening, comprising: holdingthe first panel against movement away from said one end; moving thepacking panel to pack a batch of refuse into the compartment at said oneend thereof against the first panel; sensing the packing force exertedby the packing panel on said batch of refuse; and releasing the firstpanel for movement away from said one end when said packing forcereaches a predetermined value sufficient to provide the desiredcompaction, said predetermined value remaining substantially constantfor all degrees of compartment filling.
 2. The method as claimed inclaim 1, wherein the first panel is released for movement away from saidone end in progressive steps, one step each time said packing forcereaches said predetermined valve.
 3. The method as defined in claim 1,further including the step of reestablishing said holding step followingthe performance of said releasing step.
 4. The method as defined inclaim 1, further including repeating said holding, moving, sensing andreleasing steps in a plurality of cycles of said steps.
 5. The method asclaimed in claim 1, comprising the further step of moving the firstpanel toward said one end to force packed refuse out of the storagecompartment.